Self-injury may start early in some kids: study

"What's important is to react in a way that conveys the parent cares about their child, and to act in a calming way and a non-judgmental way," Lewis, who wasn't involved in the new study, told Reuters Health.

"For parents, the first step would be to talk to their child about it, to try to understand what's going on -- what's motivating it, and what might be going on in the child's life that's contributing to it."

That could be relationships with friends, for example, or trouble at school that kids don't know how to deal with, Lewis added.

"Clearly the 1.5 percent who are meeting criteria, they're pretty serious," Hankin said. "But even those who are doing it once or twice, hopefully they can get some kind of help, because the concern is that can lead to something further," such as suicidal feelings or generally poor health.

"The bright side is, typically anxiety and depression as well as (self-injury) are very treatable," Pastyrnak, who also wasn't involved in the new study, told Reuters Health.

Psychologists might teach kids skills such as muscle relaxation, breathing and positive self-talk to help them cope with negative feelings, he added.

"With the right help, these things don't have to be long-term problems for kids."